Ultraviolet light emitting device

Abstract

The bonding layer bonds the electrode on the first surface of the ultraviolet light emitting element and a part of the mounting surface of the substrate. The adhesive layer adheres the substrate to the light transmitting member. The substrate and the light transmitting member are disposed in a state where the ultraviolet light emitting element is sandwiched therebetween. The fluorocarbon compound is a liquid at normal temperature and pressure. The fluorocarbon compound fills a gap between the second surface of the ultraviolet light emitting element and the light transmitting member in a state of being in contact with the second surface and the light transmitting member. The fluorocarbon compound is in contact with the side surface of the ultraviolet light emitting element. The fluorocarbon compound is not in contact with the adhesive layer.

What is claimed is: 
     
       1. An ultraviolet light emitting device, comprising:
 a substrate; 
 an ultraviolet light emitting element; 
 a bonding layer; 
 a light transmitting member; 
 an adhesive layer; and 
 a fluorocarbon compound, 
 wherein:
 the substrate has a mounting surface mounting the ultraviolet light emitting element; 
 the ultraviolet light emitting element has a first surface having an electrode, a second surface opposite to the first surface, and a side surface; 
 the bonding layer bonds the electrode on the first surface of the ultraviolet light emitting element and a part of the mounting surface of the substrate; 
 the light transmitting member is configured to transmit ultraviolet light; 
 the adhesive layer adheres the substrate directly to the light transmitting member; 
 the substrate and the light transmitting member are disposed in a state where the ultraviolet light emitting element is sandwiched therebetween; 
 the fluorocarbon compound is a liquid at normal temperature and pressure; 
 the fluorocarbon compound fills a gap between the second surface of the ultraviolet light emitting element and the light transmitting member in a state of being in contact with the second surface and the light transmitting member; 
 the fluorocarbon compound is in contact with the side surface of the ultraviolet light emitting element; 
 the fluorocarbon compound is not in contact with the adhesive layer; and 
 a surface of the light transmitting member and the second surface of the ultraviolet light emitting element are coplanar. 
 
 
     
     
       2. The ultraviolet light emitting device according to  claim 1 , further comprising:
 an air layer, wherein: 
 the air layer is located between the substrate and the light transmitting member; and 
 the air layer is in contact with the fluorocarbon compound and the adhesive layer. 
 
     
     
       3. The ultraviolet light emitting device according to  claim 2 , wherein:
 the air layer surrounds a periphery of the ultraviolet light emitting element; and 
 the fluorocarbon compound is present between the air layer and the ultraviolet light emitting element. 
 
     
     
       4. The ultraviolet light emitting device according to  claim 2 , wherein:
 a distance from a point in the air layer located farthest from the mounting surface of the substrate to the mounting surface of the substrate is larger than a distance from the second surface of the ultraviolet light emitting element to the mounting surface of the substrate. 
 
     
     
       5. The ultraviolet light emitting device according to  claim 2 , wherein:
 a distance from a point in the air layer located farthest from the mounting surface of the substrate to the mounting surface of the substrate is smaller than a distance from the second surface of the ultraviolet light emitting element to the mounting surface of the substrate. 
 
     
     
       6. The ultraviolet light emitting device according to  claim 1 , wherein:
 the fluorocarbon compound is not in contact with the mounting surface of the substrate. 
 
     
     
       7. The ultraviolet light emitting device according to  claim 1 , wherein:
 the fluorocarbon compound is not in contact with the bonding layer. 
 
     
     
       8. The ultraviolet light emitting device according to  claim 1 , wherein:
 a thickness of the fluorocarbon compound in contact with the side surface of the ultraviolet light emitting element increases as a distance from the mounting surface of the substrate increases. 
 
     
     
       9. The ultraviolet light emitting device according to  claim 1 , wherein:
 the fluorocarbon compound contains a filler configured to transmit ultraviolet light; and 
 the filler has a refractive index of 1.2 or more and 1.6 or less. 
 
     
     
       10. The ultraviolet light emitting device according to  claim 9 , wherein:
 the filler is a material which does not contain fluorine; and 
 a particle diameter of the filler is smaller than a peak value of an emission wavelength of the ultraviolet light emitting element. 
 
     
     
       11. The ultraviolet light emitting device according to  claim 1 , wherein:
 the light transmitting member is a lens; 
 a concave portion is formed in the lens on the mounting surface side of the substrate; and 
 the concave portion has a ceiling surface and an inner wall. 
 
     
     
       12. The ultraviolet light emitting device according to  claim 11 , wherein:
 the fluorocarbon compound is present on the inner wall. 
 
     
     
       13. The ultraviolet light emitting device according to  claim 11 , wherein:
 a distance between the second surface of the ultraviolet light emitting element and the ceiling surface of the lens is 0.1 μm or more and 500 μm or less. 
 
     
     
       14. The ultraviolet light emitting device according to  claim 1 , wherein:
 the substrate has a wall surrounding a periphery of the ultraviolet light emitting element in a manner not in contact with the ultraviolet light emitting element; 
 the light transmitting member has a flat surface on a substrate side; 
 the adhesive layer adheres the wall of the substrate to the flat surface of the light transmitting member; and 
 a height of the wall from the mounting surface is smaller than a height of the second surface of the ultraviolet light emitting element from the mounting surface. 
 
     
     
       15. The ultraviolet light emitting device according to  claim 1 , wherein the light transmitting member includes a ceiling surface that faces the substrate and the ultraviolet light emitting element after the light transmitting member is bonded to the substrate. 
     
     
       16. An ultraviolet light emitting device, comprising:
 a substrate; 
 an ultraviolet light emitting element; 
 a bonding layer; 
 a light transmitting member; 
 an adhesive layer; and 
 a fluorocarbon compound, 
 wherein:
 the substrate has a mounting surface mounting the ultraviolet light emitting element; 
 the ultraviolet light emitting element has a first surface having an electrode, a second surface opposite to the first surface, and a side surface; 
 the bonding layer bonds the electrode on the first surface of the ultraviolet light emitting element and a part of the mounting surface of the substrate; 
 the light transmitting member is configured to transmit ultraviolet light; 
 the adhesive layer adheres the substrate directly to the light transmitting member; 
 the substrate and the light transmitting member are disposed in a state where the ultraviolet light emitting element is sandwiched therebetween; 
 the fluorocarbon compound is a liquid at normal temperature and pressure; 
 the fluorocarbon compound fills a gap between the second surface of the ultraviolet light emitting element and the light transmitting member in a state of being in contact with the second surface and the light transmitting member; 
 the fluorocarbon compound is in contact with the side surface of the ultraviolet light emitting element; 
 the fluorocarbon compound is not in contact with the adhesive layer; 
 the light transmitting member includes a ceiling surface that faces the substrate and the ultraviolet light emitting element after the light transmitting member is bonded to the substrate; and 
 a distance from the ceiling surface of the light transmitting member to the adhesive layer is greater than a distance from the second surface of the ultraviolet light emitting element to the adhesive layer. 
 
 
     
     
       17. The ultraviolet light emitting device according to  claim 16 , wherein the light transmitting member includes:
 a flat surface that contacts the adhesive layer; and 
 an inner wall surface extending at an angle downward from the ceiling surface to the flat surface. 
 
     
     
       18. The ultraviolet light emitting device according to  claim 17 , wherein the fluorocarbon compound contacts an entirety of the inner wall surface. 
     
     
       19. An ultraviolet light emitting device, comprising:
 a substrate; 
 an ultraviolet light emitting element; 
 a bonding layer; 
 a light transmitting member; 
 an adhesive layer; 
 an air layer; and 
 a fluorocarbon compound, 
 wherein:
 the substrate has a mounting surface mounting the ultraviolet light emitting element; 
 the ultraviolet light emitting element has a first surface having an electrode, a second surface opposite to the first surface, and a side surface; 
 the bonding layer bonds the electrode on the first surface of the ultraviolet light emitting element and a part of the mounting surface of the substrate; 
 the light transmitting member is configured to transmit ultraviolet light; 
 the adhesive layer adheres the substrate to the light transmitting member; 
 the substrate and the light transmitting member are disposed in a state where the ultraviolet light emitting element is sandwiched therebetween; 
 the fluorocarbon compound is a liquid at normal temperature and pressure; 
 the fluorocarbon compound fills a gap between the second surface of the ultraviolet light emitting element and the light transmitting member in a state of being in contact with the second surface and the light transmitting member; 
 the fluorocarbon compound is in contact with the side surface of the ultraviolet light emitting element; 
 the fluorocarbon compound is not in contact with the adhesive layer, 
 the air layer is located between the substrate and the light transmitting member; 
 the air layer is in contact with the fluorocarbon compound and the adhesive layer; and 
 a distance from a point in the air layer located farthest from the mounting surface of the substrate to the mounting surface of the substrate is smaller than a distance from the second surface of the ultraviolet light emitting element to the mounting surface of the substrate.